Microwave radiometers are used to obtain information on environmental data, changes in the Earth's surface and atmosphere, weather forecasting and responding to human welfare issues, e.g. disease outbreaks, food shortage and floods. For example, microwave radiometers obtain data that can be used to measure soil moisture and freeze-thaw state for weather and water cycle processes. In another example, microwave radiometers can measure ice sheet internal temperatures at depth and snow thickness. Microwave radiometers can also obtain data on the Earth's geological structures, thermal anomalies, geomorphologic features and the distribution of vegetation. All of these factors are important in the understanding of a region, its environment and its resources. In many instances, it is necessary to obtain and analyze environmental information and data for an entire frequency band instead of a subset of the frequency band. Such environmental information and data includes RFI mitigation, ground validation, RFI surveying and RH research. In order to allow analysis of such environmental information and data for an entire frequency band, conventional practices entailed the design and construction of multiple RF front end channels for use in the radiometer, wherein each RF front end channel is dedicated to the processing a particular portion of the frequency band of interest. However, such a practice is expensive due to the significant time and expense required for the additional design, testing, calibration and construction of the additional RF front end channels.
What is needed is a radiometer that eliminates the problems and disadvantages associated with the aforementioned conventional practices.